Refrigerant compressor



NOV. 1, 1938. L, Q SHUHQLM 2,134,958

REFRI GERANT COMPRES SOR Filed July 23, 1937 5 Sheets-Sheet 2 INVENTOR.LESTER GSHUHOLM ATTORNEY.

Nov. 1, 1938. c. SHUHOLM V v REFRIGERANT COMPRESSOR 5 SheetsSheet 5Filed July 25, 1957 INVENTOR. LESTER C. SHUHOLM 12M fy 'ATTORNEY.

Nov. 1, 1938. L. c. SHUHOLM REFRIGERANT COMPRES 5 OR Filed July 23, 19375 Sheets-Sheet 5 1 n 7 w .l //J v/////////v/ T INVENTOR. LESTER C.SHUHOLM 6 ATTORNEY.

Patented Nov. 1, 1938 REFRIGERANT- CO- Application July 23,

.6 Claims.

This invention, in its generic aspects, relates to fluid compressingmachineswhich compress the fluids for the purpose of applying theirexpansive forces, when released from pressure, to perform the workrequired of them. The invention is more specifically directed to acompressing machine employed as a part of a refrigeration system.

A refrigerant compressing machine embodying the principles of myinvention consists essen-.

tially of a crank shaft or a shaft having a plurality of eccentrics, alow pressure cylinder, a

high pressure cylinder, and apiston valve cylinder, pistons of graduatedlengths and diameters operated in the cylinders, ports passing throughing rods joined to the eccentrics and the pistons,-

all having predetermined dimensions to provide the desired relationbetween them in order to operate efliciently.

The quintessence of the invention is to provide a comparatively silent,long-lived, and relatively compact refrigerant compressing machineemploying single-acting pistons for compressing the fluid in two stagesand by-passing the compressed 2 fluid through a piston valve. into thecondensing portion of the refrigeration system, while at the same timeemploying one of these pistons in directing the low pressure fluid intothe low pressure cylinder for the first step in the succeeding '0 cycleof the compressing operation.

As a corollary'to the above. object and equally important therewith isthe complete elimination of poppet or plate type valves, which normallyare the noise makers in the present type of com- -88 pression machines,and providing in lieu thereof a piston valve for the delivery act of thecompressing machine and making one of thepistons perform the dualfunction of compressing the refrigerant and by-passing low pressurerefrigerant 40 into the low pressure cylinder.

An equally important object of my invention is the provision within acompression machine of pistons adapted to compress fluids in two stagesand in theposition of ports in communication 45 with the cylinders inwhich the pistons operate, so that the refrigerant, after'beingcompressed for a predetermined amount, may be delivered, undercontinuous compression into another cylinder for compression and mayfinally be discharged I from the compression machine through a pistonvalve in communication with one of the cylinders and delivered to thecondenser under a predetermined pressure.

Another object of the invention is to permit Q only a small amount ofcompression within the .RESSOR I .ester C. Shuholm, Portland, Greg.

1937, Serial No. 155,232 (Cl. 230-183) low pressure cylinder in order tobring about a relatively slight increase in temperature in therefrigerant before it reaches the high pressure cylinder.

Another important object of my invention may be found in providing aninterrrelation and continuation of ports in a compressing machine forpermitting its operation at high speeds without appreciably reducing itsvolumetric efliciency, but, in fact, noticeably increasing itsdisplacement, and which .allows corresponding reduction in the size ofthe compressing machine resulting in a corresponding reduction in costof manufacture,installation, and operation.

Other objects and advantages of my invention will become apparent fromthe following detailed a description which must be read in conjunctionwith the accompanying drawings, illustrating, by way of example, thepreferred design and construction by which my invention may be put intopractice.

In the draw ngs: 1

Figure 1 is a side elevation of a compressor embodying the principles ofmy invention, parts of which are broken away to show, in cross section,the shaft housing, the cylinders, and the pistons. Figure 2 is an endelevation of the machine shown in Figure 1, partially in section andpartially broken away, to show, in cross section, the cylinders andpistons and also the relationship of some of the ports to the cylinders.

Figure 3 is a sectional, top view, taken on line 3-3 of Figure 1,looking in the direction indicated, showing the relative position of thecylinders with respect to each other.

Figure 4 is a sectional, top view, taken on line 4-4 of Figure 5,looking in the direction indicated, graphically illustrating the intakepassageway surrounding the low pressure cylinder.

Figure '5 is a sectional elevation, taken on line 5-5 of Figure 3,looking in the direction indicated, of the compressing machine embodyingthe principles of my invention, illustrating the structuralcharacteristics of the cylinders and pistons and the relationshipbetween the various portsto the pistons, the cylinders, and to eachother.

Figure 6 is a plan view showing the cylinderblock coverplate or head.

Figures 7 to 14 inclusive are semi-diagrammatic views of the cylindersand pistons embodying the principles of my invention, looking from thevalve cylinder end of the compressing machine, graphically illustratingthe positions the pistons assume during the various stages in a complete-compression cycle of operation and illustrating the relative importanceof the positions of the ports and pistons for the efficient operation ofa compression machine embodying the principles of my invention.

In the several views of the drawings, like reference characters areemployed in referring to identical parts.

In Figures 1 and 2 is shown the casing or shaft housing and relatedassembly which is generally designated by reference character A. Since,in most instances, electricity will be the source of power, it may beassumed that housing exemplifies the casing of an electric motor fromwhich shaft 2 extends. A compressor embodying the present invention maybe made to operate at a shaft of the source of power, it is of courseob.--

vious that shaft 2 may be made independent from the shaft of the sourceof power but suitablysecured thereto. Housing I is held against shafthousing 3 by any desirable means as by a bolt and nut connection asshown by reference numeral 4, The manner of mounting shaft 2 in shafthousing 3 is clearly shown in Figure .1 wherein suitable bearings 5 and6 support the shaft within theshaft housing.

A cylinder block or casing is superimposed and removably secured to thetop of the shaft housing 3 by any desirable means as by the means shownby reference numeral 8. Incorporated within the cylinder block or casingand in communication with the interior of the shaft housing 3 are a lowpressure cylinder 9, a high pressure cylinder l0 and a valve cylinderThe low pressure cylinder 9 is positioned with respect to shaft 2 sothat its axis is offset laterally on one side of the axis of said shaft;the high pressure cylinder I0 is positioned with respect 'to shaft 2 sothat its axis is offset laterally on the other side of the axis of saidshaft; and the valve piston cylinder II is positioned with respect toshaft 2 so that its axis is in alignment with and intersects the axis ofsaid shaft. This axial relationship between the shaft and the cylindersis graphically shown in Figures 1 and 2. The reason for and advantagesderived from this arrangement will be pointed out later. The cylindershave other structural characteristics which will be more fully describedshortly.

The cylinder block or casing-1 isprovided with a cylinder block coverplate l2 equipped with cooling flanges l3. Additional cooling flanges Mare formed around the upper portion of the cylinder block or casing I.The low pressure cylinder 9 and the high pressure cylinder III areequipped with cylinder heads I5 and I6 respectively, their positionbeing graphically shown in Figure 5. It will be seen from Figure 5 that,in comparison with the size and position assumed by cylinder head ||i incylinder in, cylinder head i5 is larger and enters into cylinder9 for agreater distance. These heads are spaced from the cylinderblock coverplate l2 and yieldingly held in place within the respective cylinders bythe compressed resilient members I1 and I8 respectively. This mode ofconstruction and assembly efiectively serves to' prevent any damage tothe cylinders or pistons operating therein in case any non-compressiblematter finds its way between the cylinder heads and the pistons,hereafter to be fully described.

A piston I9 is reciprocably disposed within the low pressure cylinder 9;another piston 29, having a hollow chamber 20A within itself, isreciprocably disposed within the high pressure cylinder I0; and a pistonvalve 2| is reciprocably disposed within the piston valve cylinder I I.The low and high pressure cylinders and their respective pistons act tocompress the refrigerant in two stages of compression, and the valvecylinder and its piston'valve serve to deliver this fully compressedrefrigerant to the condensing side of the refrigeration system.

Attention is now directed. to eccentrics 22, 23, and 24 which may beremovably secured to or made an integral part of shaft 2. It is well topoint out at this time that the shaft may possess therein the desirednumber of cranks instead of eccentrics in order to perform the workintended without departing from the invention. The size and position ofthe eccentrics upon the shaft are completely controlled by the strokesintended to be made by the respective pistons, as well as their timing.Eccentries 22 and 23 are positioned on the shaft so that the angularrelations of their axes with relation to the axis of the shaft arepartially opposed to each other and are controlled by the timing desiredin the operation of a compressing machine embodying the invention.

Adjustment for eccentric 24 is provided by the use of an eccentric camflange 25 shown in Figure l'in full line and in Figure 2 in dotted line.Extending through flange 25 and passing through slots 26 and 21 formedin eccentric 24 are bolts and nut assemblies 28 and 29. By this meansthe angular position of the eccentric 24 upon the shaft 2'may be readilyadjusted. This simple means of adjusting the eccentric 24 on the flange25 is merely illustrative and should not be considered as limitational.

Eccentric collars 39, 3|, and 32 are revolvably secured to eccentrics22, 23, and 24 respectively. Secured'to these collars, are connectingrods, 34, and 35 respectively. Connecting rod 35 is made of two partswhich are threadably engageable with each other for providing verticaladjustment between them. Some other method of providing this adjustmentmay, however, beutilized without departing from the invention. ,Con-

necting rod 33 is operatively connected to piston l9 through the mediumof piston pin 35 which is mounted in bosses 31. Connecting rod 34 isoperatively connected to piston 20 through the medium'of a piston pin,not shown, which is mounted in bosses 39. Connecting rod 35 isoperatively connected to piston valve 2| through the medium of a balland socket joint 35A embodying standard construction. By providing thistype of connection between piston valve 2| and connecting rod 35 greaterfacility in making any desired adjustment is provided.

A chamber or inlet passageway 39 surrounds the greater portion of thelow pressure cylinder 9 and communicates with the interior of saidcylinder, as best shown at 40, in Figures 1 and 2, permitting the intakeof low pressure refrigerant into cylinder 9. A refrigerant intake pipe4|, leading from the evaporator in a refrigeration system (not shown) issecured to and communicates with the chamber or inlet passageway 39. Therefrigerant is directed from the chamber or inlet passageway 39 towardthe interior of the low pressure cylinder 9.

A port 42 passes through the complementary wall 43 disposed between thelow pressure cylinder 9 and the high pressure cylinder I9 and connectsthe top portion of cylinder 9 with the substantially middle section ofcylinder ID. A discharge port 44 is provided at the top of the highpressure cylinder l0 and communicates with and 4 leads into the valvecylinder II. This port is opened and closed by the piston valve 2|. Thehigh pressure cylinder I0 is provided with an auxiliary inlet port 45substantially midway between the top and bottom of the cylinder whichcommunicates with passageway 39. The auxiliary inlet port 45 formed inthe high pressure cylinder is arranged to coincide with a like port 46formed substantially midway between th top and bottom portion of thepiston 20, when the piston arrives at a predetermined location duringits reciprocation. This intermittent alignment between the auxiliaryinlet port 45 and port 46 assures the periodic communication betweenchamber 39 and chamber 20A found within piston 20. An outlet port 47 isarranged substantially near the top of the piston 20 for operativecommunication withport 42. When these two ports meet, the low pressuregas, which has previously entered into the chamber 20A in piston 20through ports .45

and 46 by virtue of the periodic communication between chambers 39 and20A as pointed out before, is admitted into low pressure cylinder 9.

The various relationships between the ports heretofore referred to maybest be seen by an examination of Figure 5 and may be obtained from themode of operation hereafter to be related.

A discharge or delivery pipe 48 communicates with and leads from the topof valve cylinder II and passes through the cylinder block eoverplatel2. This pipe carries the fully compressed refrigerant to the condenser(not shown).

Modus operandi This completes the detailed description of the inventionas'embodied in the drawings. However, in order to more fully explain theoperation of a compressing machine embodying the principles of myinvention, it is well to give detailed analysis of the sequences ofoperation and, as an aid to the full understanding of this invention,there are presented eight views in the drawings, covered by Figures '7to 14 inclusive, which should be referred to and examined in connectionwith the following analysis of the mode of operation:

The eight diagrammatic views show the relative positions thepistons-assume at different portions of their respective strokes.Furthermore, they graphically point out the degree of circular motion ofthe eccentrics in relation to the reciprocation of the pistons, securedby having the center lines of cylinders 9 and Ill offset from the axisof the shaft 2.

In Figures 7 to 14 inclusive, curved shaft arrows indicate the directionof the rotation of the eccentrics 22, 23, and 24 as counter-clockwise.These eccentrics are connectedto pistons I9, 20, and 2| respectively bythe connecting rods 33, 34, and 35, shown by dash and double-dottedcenter lines.

In order that a full understanding of the operation of a compressingmachine embodying my invention may be had from the views covered byFigures '7 to 14 inclusive, the ports and their relation are showneither in full or dotted line even where these ports cannot actually beseen in the views as depicted. I

It will be assumed that the cycleof operation begins with the piston l9substantially at the bottom of its stroke as shown 'in Figure 7. Whenpiston |9 is'in the position shown in Figure 7,

piston 20 has begun its downward stroke and piston valve 2| is abouthalf way on its upward stroke, having previously sealed port 44. Therelative positions of the pistonswith relation to the various ports andto each other, as shown in Figure '7, indicates that piston l9 hasuncovered its upward stroke and has covered port 40 and is now in aposition to compress the trapped refrigerant in piston 9. Piston 20 hasprogressed sufficiently on its downward stroke to permit ports 45 and 46to communicate sufliciently to allow the entrance into chamber 20A oflow pressure refrigerant from passageway 39 and has previously sealedport 42 before port 40 has been closed by piston I9, and finally pistonvalve 2| has about reached the limit of its upward stroke.

When the cycle of operation has reached the position shown in Figure 9,piston l9 has progressed sufliciently within cylinder 9 to havecompressed in some degree the trapped refrigerant, while piston 20 hasmoved downwardly within cylinder III to have exposed port 42sufliciently to permit the refrigerant heretofore compressed in cylinder9 by piston Hi to enter into cylinder I6, and the piston valve I hasreached the highestpoint in its stroke. It is to be noted that the majorpart of the partially compressed refrigerant is now to be transferred tohigh pressure cylinder l0 and that very little compressing takes placeduring and between the two stages in the cycle of operation shown inFigures 9 and 10.

When the cycle of operation has reached the position shown in Figure 10,piston i9 is completing its upward stroke; while, at the same time,piston 20 has reached the bottom of its stroke and has completelyuncovered port 42, so that the compressed refrigerant enters cylinder l0unimpeded. In this stage of the operation the piston valve H has startedits downward stroke. Continuing the cycle of operation, it may be .seenfrom Figure 11 that piston 9 has reached the top of its stroke andpiston 20 has advanced sufficiently on its upward stroke-to completelyclose port 42 and that the closing of port 42 by piston 26 occurs beforepiston l9 has made any appreciable progress on its downward stroke.

, The piston valve 2| has progressed on its downstages in the cycle ofoperation illustrated in Figures '7 to 11.inc1usive, the port 44 was atall times retained in a sealed condition by the piston valve 2|. It isonly after the stage in the cycle of operation reached as illustrated inFigure 12, that port 44 is first unsealed .by the downward progressionof the piston valve 2|. this stage of the cycle of operation, the pistoni9 has made some progress on its downward stroke while the piston 20 hasprogressed towards the completion ofv its upward stroke sumciently tohave compressed the refrigerant to a predetermined pressure normallyequal to the pressure sealed.

During- In Figure 13 the progression and retrogression of the variouspistons is shown more fully advanced. It will be seen that piston '20has progressed on its upward stroke to a point which permits a portionof port 42 to coincide with a portion of port 41, thus permitting theinflow of refrigerant into cylinder 9 from chamber 20A before piston l9has traveled any great distance on its downward stroke. Piston valve 2|has traveled downwardly sufiiciently to nearly completely unseal port 44through which the fully compressed refrigerant is now passing.

In Figure 14 is depicted the position of the various pistons when onecycle of operation has been nearly completed. In this figure, piston I9is about to reach the limit of its downward stroke and uncover port 40.Piston 20 has reached the limit of its upward stroke and has heretoforedriven the fully compressed refrigerant into cylinder ll through port44, and piston valve 2| is now engaged in completing the sealing of port44 before piston 20 will have dropped appreciably in its downwardstroke. This view also graphically shows that no gas can now enter intochamber 20A through ports 45 and 46 since this passage is closed; butthe gas heretofore trapped within chamber 20A has been delivered intocylinder 9, and piston I9 is about to unseal port 40 in order to admitmore gas from inlet passageway 39 to complement the gas already drawninto cylinder 9 by the good oflices of chamber 20A formed in piston 20.

It will be seen that by having the axes of cylinders 9 and I offsetlaterally on the opposite sides of the shaft and therefore notintersecting the center line of the driving shaft, a relationship isestablished between the circular motion of the driving eccentrics andthe rectilinear mo- .tion of the pistons which provides the relationshipabsolutely necessary to produce theparticular sequence of timing theopening and closing of the ports, without which timing the invention ascontemplated could not operate,

.The invention has been described in connection' with a specific,illustrated embodiment. However, it should be understood that theinvention in its broader aspect is not limited to the specificconstruction herein shown and described since changes in the size,proportion, and mechanical relations, as well as additions, omissions,and substitutions may be made in the construction and assemblyby thoseskilled in the art without departing from the broad'aspect of thisinvention.

Having thus disclosed the invention, what is claimed as new and usefuland upon which it is desired to secure Letters Patent is:

1. In combination, a low pressure cylinder; a piston operating therein;a high pressure cylinder; a piston operating in said high pressurecylinder, there being cooperating ports in the cylinder wall to controlthe intake and exhaust of the low pressure cylinder and to'transfer saidexhaust to the high pressure cylinder; and a separate valve controllingthe exhaust of said high pressure cylinder.

In combination, a low pressure cylinder; a

piston operating therein; a high pressure cylinder; a piston operatingin said high pressure cylinder and provided with ,an interior valvechamber, there being cooperating ports in the cylinder walls to controlthe intake and exhaust of the low pressure cylinder and to transfer saidexhaust to the high pressure cylinder; and a separate valve controllingthe exhaust of said high pressure cylinder.

3. In combination, a shaft; a low pressure cylinder in operativeassociation therewith and arranged with its axis offset on one side ofthe. axis of said shaft; a high pressure cylinder in operativeassociation with said shaft and arranged with its axis offset on theother side of the axis of said shaft; a piston operating in said highpressure cylinder and provided with an-interior chamber, there beingcooperating ports in the cylinder walls to control the intake andexhaust of the low pressure cylinder and to transfer said exhaust to thehigh pressure cylinder, and a separate valve controlling the exhaust ofsaid high pressure cylinder.

4. In a compressing machine of the class described in combination, arotative member, a plurality of cylinders, pistons reciprocatingtherein, operative connections from the pistons to said rotative member,means on said rotative member to give rectilinear motion to saidpistons, adjustable means associated with the first-mentioned means tovary the angular position of the throw for permitting the use of one ormore types of refrigerants at their most efiicient working pressure theaxes of the cylinders being not in the plane of the axis of the rotativemember projected parallel the axes of the cylinders.

In a compressing machine of the class described, in combination, arotative member, a plurality of cylinders, pistons reciprocatingtherein, operative connections from said pistons to said rotativemember, means disposed upon said rotative member to give rectilinearmotion to said pistons, the axes of the cylinders being not in the planeof the axis of the rotative member projected parallel to the axes of thecylinders, and

means for changing the relative angular positions of the rotative meanswhich give rectilinear motion to said pistons for permitting the use ofone or more types of refrigerants at their most eflicient workingpressure.

6. In'a compressing machine of the class described, in combination, aplurality of cylinders,

reciprocating pistons therein, a closed chamber in the high pressurepiston, passages conducting primary pressure refrigerant to portsadmitting it to the closed chamber of the high pressure piss ton duringpart of its stroke, ports arranged to

